Microbial Potential for Ecosystem N Loss Is Increased by Experimental N Deposition

作者：Freedman Zachary B^*; Upchurch Rima A; Zak Donald R

来源：PLos One, 2016, 11(10): e0164531.

DOI：10.1371/journal.pone.0164531

Fossil fuel combustion and fertilizer use has increased the amount of biologically available N entering terrestrial ecosystems. Nonetheless, our understanding of how anthropogenic N may alter the physiological mechanisms by which soil microorganisms cycle N in soil is still developing. Here, we applied shotgun metagenomics to a replicated long-term field experiment to determine how two decades of experimental N deposition, at a rate expected by mid-century, has affected the genetic potential of the soil microbial community to cycle N in soils. Experimental N deposition lead to a significant and persistent increase in functional assemblages mediating N cycle transformations associated with ecosystem N loss (i. e., denitrification and nitrification), whereas functional assemblages associated with N input and retention (i. e., N fixation and microbial N assimilation) were less positively affected. Furthermore, the abundance and composition of microbial taxa, as well as functional assemblages involved in housekeeping functions (i. e., DNA replication) were unaffected by experimental N deposition. Taken together, our results suggest that functional genes and gene pathways associated with ecosystem N loss have been favored by experimental N deposition, which may represent a genetic mechanism fostering increased N loss as anthropogenic N deposition increases in the future.

• 出版日期2016-10-13